Coupled Thermodynamic and Kinetic Changes in the Electrochemistry of Ferrocenyl Monolayers Induced by Light
MetadataShow full item record
Funding and Sponsorship
© 2017 American Chemical Society.We report on the light-induced systematic changes to the thermodynamics and kinetics of ferrocene units attached to a n-type silicon(100) photoelectrode. Both the reaction rate and the energetics of the charge transfer are simultaneously affected by changes in the intensity of the incident light. Cyclic voltammetry shows that increases in the intensity of illumination can drive the redox process toward less positive potentials, with a downhill shift in E1/2 of ca. 160 mV by increasing the light intensity from 3 to 94 mW cm-2. However, this thermodynamic shift is paralleled by an increase in the kinetics of the charge transfer. This latter observation - light-induced kinetic effects at monolayers on silicon electrodes - is made possible only by the stability of the surface chemistry construct. Furthermore, electrochemical impedance measurements showed that the electrodes exhibit faster electron-transfer kinetics under illumination than previously reported for ferrocene-terminated highly doped silicon (around 1 order of magnitude faster). An explanation for the kinetic effects is proposed on the basis of the consistent increase in photogenerated charge carriers inside silicon and the enlarged potential difference between the valence band of silicon and the surface-attached ferrocene.
Showing items related by title, author, creator and subject.
Light Activated Electrochemistry: Light Intensity and pH Dependence on Electrochemical Performance of Anthraquinone Derivatized SiliconYang, Y.; Ciampi, Simone; Choudhury, M.; Gooding, J. (2016)We seek to understand how the thermodynamics and kinetics of anthraquinone-containing self-assembled monolayer on silicon electrodes are affected by two key experimental variables: the intensity of the light assisting the ...
Light-activated electrochemistry on alkyne-terminated Si(100) surfaces towards solution-based redox probesWu, Y.; Kashi, M.; Yang, Y.; Gonçales, V.; Ciampi, Simone; Tilley, R.; Gooding, J. (2016)Light-activated electrochemistry is a powerful concept, where faradaic electrochemistry at a monolayer protected monolithic silicon electrode can be ‘turned on’ at any location with micron scale resolution simply by ...
Nanocrystal Inks: Photoelectrochemical Printing of Cu2O Nanocrystals on Silicon with 2D Control on Polyhedral ShapesVogel, Y.; Gonçales, V.; Al-Obaidi, L.; Gooding, J.; Darwish, Nadim; Ciampi, Simone (2018)Here, a printing technology is reported that enables the functionalization of photoconducting materials with an arbitrary user-defined pattern of nanocrystals. Two sets of information can be encoded into the same unit ...